Relative Importance and Seasonal Activity of Cochlimyia Americana C. & P. And Other Wound-infesting Blowflies, Valdosta, Ga., 1935–1936

Abstract

The primary screwworm fly, C. americana, is the most important species causing wound myiasis of animals in the vicinity of Valdosta, Georgia. Wounds around which the wool had been clipped on the shoulders of sheep were the most attractive to C. a., and unclipped shoulder wounds of goats were second in attractiveness. Unclipped shoulder wounds of sheep were the least attractive, but this type of wound was the most attractive to the secondary blowfly, C. macellaria. In the types of wounds studied, the height of attractiveness for C. a. is reached on about the 5th-7th day. C. a. appeared to be as active on days when the max. air temp. reached 75[degree]F as on days when the temp. was 80[degree]. Activity is greatly decreased when air temps. fall below 70[degree]. A min. temp. of 24[degree] apparently did not kill adults in nature. C. m., Phormia spp., Lucilia spp., and Sarcophaga spp. were the only secondary flies found to initiate infestations of wounds. Sheep were more susceptible to infestations by secondary blowflies than were goats or calves. Of the various spp. of secondary blowflies, C. m. caused more infestations during the period from Aug. to Oct.; Phormia spp. predominated from Nov. to March, and Lucilia spp. from Apr. to July.